help with DIY tune

CantSitStill

Specialist
Jul 22, 2022
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Hi,

Hope someone can offer some advice here. I'm finally getting to grips with turning my car myself. I have the WOT stuff fairly well worked out and I'm trying to make the car feel more refined now. I have an issue in sport mode where under light acceleration it suddenly tries to go way too fast. It feels very aggressive. I have the MHD throttle delay setting applied at 30%, down from 50% as a test but this did nothing. Here it is in a log where you can see at 30% accelerator it suddenly goes full throttle. Can anyone educate me as to why this might be happening:


I don't get why the DME decided to go from 27% throttle to full in such a short period.

Thanks
 

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byebyeVTEC

New Member
Jun 14, 2023
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Did you figure this out?

Looks like you just have your load targets set too aggressively, it's opening throttle because that's what is required to meet your load target.
 

CantSitStill

Specialist
Jul 22, 2022
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Hi yes I did. It was because I had messed with the wgdc floor table and set it to 37 to get the wastegates above that point to stop rattle. Seems that the boost was then on and off sort of thing as 37 + the base and other tables added was a min of about 47% wgdc which was not allowing the dme to taper the boost on smoothly. Went back to a tune before that with the wgdc at its normal 12.7 and it's great. Motto is you can't tune out hardware issues
 

Hexaux

New Member
Apr 24, 2022
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I was having similar rattle issues with my upgraded turbos but through a fair bit of testing managed to tune it out with both pre-control A and base instead of the floor (so it can still go lower in regions where you couldn't hear it anyway) but it seems to balancing act as far as overboosting at low boost setpoint and mid maf areas. Have you figured out roughly what boost setpoint and maf req (wgdc) regions your rattle is at? Mine was in the 1-1.18 and 30-60 g/s area. Also I have had no issue running 220 load target across the board as I found trying to taper it in made inconsistent load targets and general predictability in lighter acceleration, somewhat like yours. Maybe try that and let mhd's 3d table limit boost for you
 
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CantSitStill

Specialist
Jul 22, 2022
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Rattle was happening most of that log. No set point logged but you can see the wgdc/maf.

I fixed it by adding a wave washer that I cut open to an exact size and clipped between the flapper and wastegate arm to take up the play. Might cause other issues but basically I was ready to sell the motor due to it so thought I would give it a try. So far working well and proved its too much play on the flappers. Spool is the same.
 
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Hexaux

New Member
Apr 24, 2022
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If that's the case it seams to be under 60g's maf so pre control A should be able to handle it for you. I'd set your floor back to stock and set every pre control A cell 4000 rpm and under way high (say 50 which should max out your logged base wgdc value) and decrease it by ten until you find the values that keep bank 1 wgdc above the 30-40 you need. Thats what I did along with just a little in the top left of base wgdc for my situation
 

Hexaux

New Member
Apr 24, 2022
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And your throttle plate jump seems to be in the rpm range where you move from 150 to 220 load request. I found anything other then having it flat cause weird changes. Your turbos are probably not going to spool to 15+ psi under 2500 so I figure give the dme a non moving limit which in my experience helps it correct for itself better. The mhd boost ceiling should just cap the boost target at the end of the standard calculations where you want just fine
 

CantSitStill

Specialist
Jul 22, 2022
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Hi. Thanks for the advice. With the wgdc floor at normal values my my tuner did try using pre control A but the rattle happens just as it requests boost so did not help the rattle for me. We did manage to get it to stop somewhat by increasing the base in certain areas but it only worked for a while then would happen again going up hills with marginal throttle. I just got sold duff turbos. The fix I did with the wave washer has stopped it for now. There was about 0.8mm of room believe it or not to slide a washer in.
 

CantSitStill

Specialist
Jul 22, 2022
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That's another log where precontrol A was used but it seemed to be off that table and wgdc was about 32%. I needed to keep wgdc about 40% to stop it. I played around with the jb4 to test it where I could adjust that on the fly. It would let me keep it about 38% min but it was surging on the boost at lower rpm's and started creating other issues. Rattle was just there in no more so I think it needs to be about 40 to fully stop
 

CantSitStill

Specialist
Jul 22, 2022
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Actually I just checked my emails and I sent the tuner that precontrol A table to try and change but he never actually said he did but the next revision did change where the wastegates sat at default off the throttle so I assumed he had tried to use that but I can see the table goes right up to 60 maf so maybe he never?? Does it always use this table at everything below?
 

Hexaux

New Member
Apr 24, 2022
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I believe so, between that and playing around with the top left 3x3 cells of base and spool base that's how I sorted it out